GE Kelman TRANSFIX 1.6 Installation Manual page 41

D.5 6 mm Tubing Adaptors
If ¼ in. tubing is not available, 6 mm stainless steel tubing may be used, but the
maximum tubing run may be reduced, and ¼ in. to 6 mm tubing adaptors must be used.
Consult with the GE Customer Service Centre. The adaptors should be Swagelok (SS-6M0-
R-4 Stainless Reducer, 6 mm OD – ¼ in. OD) or Ham-Let (767LT SS Stainless Reducer, 6
mm OD – ¼ in. OD). At least eight of these are required for the installation.
Do not use 6 mm tubing without the above adaptors. To do so would void the
warranty.
D.6 Tubing Material
Stainless steel is the only material that should be used. The use of any other
tubing material will cause reliability issues or inaccurate results and void the
warranty of the product. GE does not support the use of copper tubing for the
installation of its transformer analysis products. The reasons for this are
outlined below.
D.6.1 Flow Rate
The solid seamless stainless steel tubing that GE specifies is 316 Stainless Steel, 1/4 in. OD
with a 0.035 in. thick wall. Most 1/4 in. copper tubing has a greater wall thickness which
reduces the flow rate rendering it too fragile to place in the field. Bends in standard soft
copper tubing crush and deform more easily, which can reduce the flow rate than would
otherwise be the case with properly bent stainless steel tubing.
D.6.2 Connection reliability and physical damage
GE has two overriding primary design and installation principles:
Never let oil out of the customer's transformer during operation.
Never let air into the customer's transformer during operation.
Copper tubing, in general, is too soft to create a reliable long term seal at the connections
in the vibratory environment of a transformer; the connections will eventually leak. The
softness of copper tubing also make it prone to damage after the installation; it can
easily get kinked, pinched and even torn from the connection by maintenance and
service activities near the transformer.
MA-001 – TRANSFIX-family Installation Manual – Rev 3.0 18-Jan-16 Page 41 of 55